A multiplicity of television cameras are used at the present time to televise sporting events, such as football, basketball, golf and hockey games, as well as races, and the like. Each camera is monitored by a program editor, and the program editor determines the camera selection in order that the game in progress may be televised from the best camera angle and position as the action moves about the playing area.
Each cameraman pans his camera to follow the action, and he also zooms his camera into the point of action when appropriate in order to reproduce the action either on a close-up or long-shot basis, whichever is warranted at any particular time.
It is the present practice for the cameraman to adjust the focus of his camera manually as the camera is panned and whenever the zoom control is activated. The focus control usually comprises a manually operated mechanical, or electro-mechanical device mounted adjacent to the left of the two panning handles of the television camera, and the presentday television camera also usually includes a zoom control in the form of a second mechanical or electronically activated device adjacent to the right panning handle of the camera.
Then, as the cameraman pans his camera to follow the action on the playing field, he turns the focus control handle in an attempt manually to maintain the camera in focus during the panning operation. Also, when the cameraman zooms in on the action, he must also adjust the focus control to keep the camera in focus as closely as possible.
It is obvious that there are limits in the prior art to the ability of the cameraman manually to keep his camera in focus at all times, especially when the action is rapid and he is attempting to follow, for example, the flight of a ball or puck. In accordance with the present invention, the television cameras are all computer controlled so that each is automatically maintained in focus regardless of how fast moving the action may be, so that the cameraman need merely to pan his camera to follow the action, and to zoom in on the action, without any necessity to manually control the focus during any of these operations.
In broadcast sports television today, the prevailing practice is to place the cameras perpendicular to the general path of action so as to minimize focusing problems. However, this camera placement maximizes the necessary panning action of the cameras and introduces panning problems as the cameras attempt to follow rapid action. These problems include improper framing, or losing the action from the camera frame, or blurring the action due to panning at the wrong speed. One objective of the system of the invention is to overcome to a large extent the foregoing panning problems by permitting more favorable camera placements.
The system of the invention makes possible many exciting camera angles by following a ball or puck, for example, during a ball game or a hockey game, and for maintaining perfect focus at all times which is beyond the capabilities of the prior art manually focused cameras. In brief, the improved control system of the present invention serves to instantaneously and automatically maintain each television camera of a plurality of cameras used for televising a sporting event, and the like, in perfect focus as the cameras are panned and zoomed to follow the game action, so as to obviate any need for the cameraman to concern himself in any way with the focusing of his television camera.
The system of the invention has many significant advantages over manual focusing systems and existing automatic focusing systems which are based on energy reflection, optical cybernetics and multiple camera triangulation. These advantages include superior speed, greater accuracy, higher resolution, greater flexibility, cost effectiveness and multiple camera capability.
Speed, as referred to above, refers to the ability of a system to operate quickly enough to maintain critical focus as cameras follow continuous rapid action, and in the case of discontinuous activity, to have the cameras already in focus as they pan to and/or zoom in on the new area of activity.
An advantage of the computerized automatic multiple camera-focusing system of the present invention lies in the ability of the operator, one who is knowledgeable in the particular sport, to anticipate and/or to react to rapid and capricious movements, and to effect the proper input to the computer by the digitizing tablet, which then immediately focuses the involved cameras. Such an operator can quickly manipulate the "depth-of-field" in the direction of the activity so that both the desired object and its eventual destination can be in focus rather than just one or the other.
The prior art optical cybernetic focusing system is unsatisfactory in rapid action sport situations because the system relies on error input in order to initiate correctional procedures. Objects moving rapidly toward or away from a camera will always be somewhat out of focus because of the lag time involved in the cybernetic system. Also, the destination of the moving objects will be out of focus as they come into frame. When cameras pan to and/or zoom in on objects far from the original focus point, the objects will be out of focus before the cybernetic correctional processes are initiated properly to focus them.
The speed of the computerized automatic multiple camera focusing system of the present invention is greater than prior art systems and camera operators because the input to the computer eliminates the tendency to wait for focusing errors to manifest. This is accomplished by the system of the invention by anticipating and/or reacting to the true direction of action and inputting that directionality as it is happening so as to maintain a sharp focus on the proper object and its eventual destination without any error signal correctional lag.
An automatic focusing control system based on energy reflection is suitable for tracing rockets heading for space, but is unsuitable in conjunction with sporting events. The accuracy of the prior art mechanical multiple-camera triangulation system depends on the concerted skill of three or more camera operators, all accurately framing the proper subject. They are constrained by looking through their lenses into viewfinders. If one or more of the operators loses the object, the entire system goes out of focus.
The computerized automatic multiple camera focusing. system of the present invention, using human intelligent inputs, is exceedingly accurate. Wherever the action in reality is, or is about to be, the operator moves the electronic pen on the tablet. Lenses are never accidentally set at infinity, nor are they set to focus on irrelevant foregrounds leaving the true objects of focus and their destinations blurred.